The objective of this research is to determine the structure of anticancer agents, both synthetic and those isolated from marine organisms, using single crystal x-ray diffraction. The compounds are in the following categories: carbon-phosphorous heterocycles, azasteroids and their complexes with established anticancer drugs and compounds responsible for the confirmed tumor-inhibitory activity exhibited by extracts of a number of marine organisms. The undersigned agrees to accept responsibility for the scientific and technical conduct of the research project and for provision of required progress reports if a grant is awarded as the result of this application.